I have said this in the past I know, but it is still something that annoys me to no end.
Diablo 3 has one major upside to every other ARPG I have ever played. When you use a melee attack on the ground with any button you move. When you get in range for your attack, you attack the nearest enemy.
I know you can do something similar with the left mouse button, but it doesnt work how I would hope. The issue is that it will not swap from just walking to attacking when you hit shift or move the cursor over an enemy, you just keep moving. This means that it is effectively no different than letting off the mouse button and pressing the skill button. Aka, it does nothing.
There is one exception to this and it is closer to what I would like. If you use it with Mana Strike, when you hit shift, you stop moving and start attacking. This makes it an easy way to move around. When you want to use a stronger attack, well you just do like normal, hit the button and then swap back to using the left mouse button.
I can find no other ability to plays like that with it. I will not deny that it is probably a bug, but it is a nice QoL one though. If all abilities would work like that with it, I would be fine. No others that I have tried do though. If at the least there was an option to allow all buttons to act like that, I would be very happy.
All that said, being able to move and attack with the same button, without having to let up on the movement button, is one part of D3 that I miss in every other ARPG I have played.